There are various methods for controlling torque of an engine of a vehicle (hereinafter, referred to as ‘engine torque’) and combustion noise generated by the engine torque. Generally, the engine torque can be controlled by a parameter of IMEP (indicated mean effective pressure). The IMEP represents torque generated by combustion.
Among methods for controlling engine torque and combustion noise, a method in which the engine torque is controlled by IMEP control (IMEP is controlled by control of a main injection amount) and the combustion noise is controlled by control of a pilot injection amount is often used.
However, if the main injection amount is controlled in order to control IMEP, the combustion noise is influenced by the main injection amount. Also, if the pilot injection amount is controlled in order to control the combustion noise, IMEP is influenced by the pilot injection amount.
As described above, the main injection amount affects the combustion noise and the pilot injection amount affects IMEP. Therefore, if a relationship between the main injection amount and the pilot injection amount for controlling the IMEP and the combustion noise is ignored, a problem may result in that control for the main injection amount or the pilot injection amount is diverged.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.